Endress+Hauser COY31-Z | COS31/COS41 DO Sensor Maintenance Kit (Membrane, Electrolyte, O-rings)
Endress+Hauser COY31-Z (51506784) service kit for Oxymax COS31 & COS41 dissolved oxygen sensors. Includes membrane caps, KCl electrolyte, sealing rings & polishing strips.
Product Overview
The Endress+Hauser COY31-Z (Article No. 51506784) is the standard maintenance/spare parts kit for Oxymax W COS31 (3-electrode) and COS41 (2-electrode) amperometric dissolved oxygen sensors. It contains all consumables required for periodic membrane replacement and electrolyte refill — including COY31-WP membrane caps, COY3-F potassium chloride (KCl) electrolyte solution, Viton O-ring seals (COY31-OR), and cathode polishing strips (COY3-PF) — ensuring continued measurement accuracy in wastewater aeration and water quality monitoring.
Technical Specifications (Kit Contents)
| Parameter | Specification |
| Model / Order Code | COY31-Z |
| E+H Article Number | 51506784 |
| Compatible Sensors | Oxymax W COS31, Oxymax W COS41 |
| Included Membrane Cap | COY31-WP (Standard Response, POM) |
| Electrolyte | COY3-F – KCl Solution (Saturated) |
| Sealing Rings | COY31-OR (Viton / FKM) |
| Cathode Polish Strips | COY3-PF (Emery Paper) |
| Pack Qty (Membrane Caps) | Typically 2 pcs |
Technical Specifications (Application & Conditions)
| Parameter | Specification |
| Product Type | Consumables / Service Kit |
| Sensor Type | Amperometric Galvanic / Clark-type DO Sensor |
| Application Area | Wastewater, Surface Water, Aquaculture |
| Recommended Service Interval | 3–6 months (process dependent) |
| Fast-Response Variant Kit | COY31-S-Z (separate item, for COS31-S) |
Key Features
-
Complete Service Package: Bundles membrane, electrolyte, seals, and polish strips — no separate sourcing needed.
-
Genuine OEM Match: Ensures chemical compatibility and measurement traceability with COS31/COS41 sensors.
-
Standard vs. Fast Response: This kit (COY31-Z) fits standard-response sensors; fast-response COS31-S requires COY31-S-Z.
-
Extended Sensor Life: Regular membrane/electrolyte renewal restores sensor performance and avoids premature sensor replacement.
Applications
-
Wastewater Aeration Basins: Routine servicing of DO probes in activated sludge process control.
-
Environmental Monitoring: Maintenance of sensors deployed in rivers, lakes, or coastal waters.
-
Aquaculture: Keeping DO probes in fish tanks and raceways within spec.
-
Industrial Effluent: Scheduled preventive maintenance in discharge monitoring stations.
Note: Membrane cap COY31-WP is also available separately (Order No. typically 51506684). Always verify sensor model (COS31/COS41) and response type before ordering.
About ACH
Founded in 2012, ACH is a top-tier distributor of industrial automation products, supplying genuine devices from leading brands like ABB, P+F, E&H, AB, MTL to emerging markets worldwide. Our mission is to provide 100% Genuine products at the most competitive prices, helping customers reduce costs and strengthen their market position.
Frequently Ask & Questions
Are preferential prices available?
Long-term brand partners can get competitive product prices. At the same time, ACH controls the profit per order to 5%, providing the most competitive prices.
Are the Products Genuine OEM Units?
Yes, all products from ACH are certified genuine OEM units. We acquire our inventory through official OEM channels and trusted third-party suppliers, ensuring every item is authentic and reliable.
How will you arrange shipment?
We'll handle the shipping for you. Through our partnerships, we can secure competitive rates with major carriers like FedEx, DHL, TNT, and UPS, ensuring a smooth and cost-effective delivery.
What is the warranty of goods?
One-year Warranty.
How long is the logistics cycle of the product?
Products are divided into spot and futures, and the delivery period of different brands of products is also different. For details, please contact the ACH business manager.
